28241

Appears in sequences

• Number of base 19 circular n-digit numbers with adjacent digits differing by 2 or less.at n=6A124947
• Semiprimes formed by inserting a semiprime between the semiprime's ordered factors.at n=8A227942
• T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.at n=29A240460
• Number of 2 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.at n=6A240461
• a(n) = 2*n^4 - floor(2^(1/4)*n)^4.at n=23A257854
• Partial sums of A299266.at n=33A299267
• G.f.: A(x) = Sum_{n>=0} x^n * (1 + (-1)^n * sqrt(A(x)))^n / (1 - (-1)^n * x*sqrt(A(x)))^(n+1).at n=8A325156
• Numbers k such that there are exactly four biquadratefree powerful numbers (A338325) between k^2 and (k+1)^2.at n=24A338391
• a(n) = abs(a(n-1) - a(n-2)) if a(n-1) and a(n-2) are both prime or both composite. a(n) = a(n-1) + a(n-2) otherwise, where a(1) = 1 and a(2) = 2 and n > 2.at n=41A341130